Parachute shell with divisible case



7 March 3, 1970 J. E. H. BERGMAN PARACHUTE SHELL WITH DIVISIBLE CASE Filed Dec. 15, 1967 IN V EN TOR. aaxwn/ae/kgmnfllvfimamam nited States Patent 3,498,220 PARACHUTE SHELL WITH DIVISIBLE CASE Johan E. H. Bergman, Hagersten, Sweden, assignor to Forsvarets Fabriksverk, Eskilstuna, Sweden, an agency of the Department of Defense of the Kingdom of Sweden Filed Dec. 15, 1967, Ser. No. 691,024 Claims priority, application Sweden, Jan. 23, 1967, 942/67 Int. Cl. F42]: 13/38 US. Cl. 10235.6 3 Claims ABSTRACT OF THE DISCLOSURE In a shell, an active body such as a smoke or luminous charge is provided with a sliding member that fits around or into a hole in a rigid push plate in the shell case and to which a parachute is attached. These parts are packed into a divsible shell case. The powder charge will, when ignited, accelerate the active body forwardly and the parachute and the tail of the shell case, backwardly. This motion continues until a stop in the free endof the sliding member is reached. The kinetic energy gained by the parts will then assist in pulling out the parachute and in spreading out the parts so that they will not contact with and destroy the parachute.

A parachute flare usually consists of a flare or a smoke charge and a parachute that reduces the rate of descent of the flare. The case of the shell should be separable such as by means of a powder charge, in such a way that the parachute can be released and unfolded without the possibility of being damaged by the parts of the case. Other disadvantages caused by the protective case are that it occupies space and increases the weight of the projectile.

SUMMARY OF THE INVENTION The present invention concerns shells of the abovementioned type and refers to an efficient manner of separating that part of the case which contains the parachute. The structure is also such that it protects the parachute. An object of the invention is to provide an active body that can move in relation to the tail to the extent of a centimeter or more so that the motion is retarded by a stopping device.

In the accompanying drawing, wherein illustrative embodiments of the invention are disclosed:

FIG. 1 shows an embodiment in longitudinal section of the device with some of the parts indicated in outline, and

FIG. 2 shows a detail on a large scale, of a longitudina section of another embodiment.

The case of the shell shown in FIG. 1 consists of a front part or nose 4 which has a time fuse with a primer 1 and a tail 15 provided with steering fins. The front part 4 surrounds an active body consisting of a container 3 for a flare or a smoke charge and by means of a separable connection 5 it is attached to the tail 15 which contains a parachute 14. In the bottom of the active body is provided a rearwardly projecting bolt 11 provided at its free end with a head 13. The bolt 11 is supported in an axially displaceable manner in a central hole formed in a push plate 9 that rests on an annular shoulder 10 in the tail 15. There is attached on the lower surface of the push plate 9 a tube 12 which surrounds the bolt 11 and has a hold for the strings of the parachute 14. Between the push plate 9 and the rear wall of the active body 3 is Ice applied a divided spacing ring 8' which forms a chamber for a powder charge and a coil spring 6. An ignition channel 2 connects this chamber with the time fuse 1 or a separate boosting charge connected to the latter. The ignition channel 2 passes through the active body 3 and has one or more connection channels not shown in the drawing, but located at the front end of the bolt 11.

FIG. 2 shows a shell case, consisting of a front part 16 which overlaps a rear part or tail 25 that is connected to the front part 16 by means of a screw thread 26 that is easily shorn off. The front part 16 encloses an active body consisting of a container 17 with a luminous body or smoke charge. A tube 18 has one end attached to a metal container 17 by a screw thread and its other end is provided with a flange that points inwardly. A screw thread 24 that is easily sheared off connects the flange to the tail 25. Between the parts of the case a push plate 20 is applied and that rests against the inside of the tube 18 along its periphery. The plate has a cover 22 engaging the upper part 23 of the tail 25, thus forming a tight cover for the parachute. The push plate forms a tightening cover that protects the parachute. The strings of the parachute are attached to the rear side of the push plate. On the inside of the tube 18 a spacing ring 19 is threadably attached to provide space for a powder charge 21.

The construction made according to FIG. 1 operates in the following manner: The shell is fired in the usual way and at the proper time the time fuse releases an igniting beam that ignites the charge 7 through the tube 2. The push plate and the active body 3 are shot apart and if the active charge is directly cast or firmly held on the front part 4 of the case, the screw thread connection 5 will be broken. If the active body 3 is loose it will not be influenced at all because the pressure from the igniting charge will balance the pressure from the charge 7. Not until the front part 4 of the case has been thrown off will the active body 3 begin to move forwardly simultaneously with the rear part or tail 15 as the tail is pushed backwardly by the push plate 9. The bolt 11 is displaced in the central hole of the push plate 9 until the head 13 hits the plate. On account of its kinetic energy that is present, the active body 3 will draw the plate 9 and the parachute out of the tail 15. The expansion of the propelling charge is utilized to give the active body and the tail a substantial relative velocity in two opposite directions so that the tail will travel far away from the parachute before the parachute has had time to unfold and be retarded. The luminous or smoke charge can also be ignited directly by the heat from the charge 7. The bottom of the active body 3 has holes (not shown) for the burning luminous charge or the produced smoke. The spring 6 will keep the active body at some distance from the push plate so that the outstream holes for the production of smoke are not clogged when the active body reaches the ground.

The device according to FIG. 2 operates in the following manner: When the charge 21 is ignited, the screw thread 26, and thereafter the thread 24 at the lower flange of the tube 18 will be shorn off. The screw thread 26 may break when the primer charge explodes. The active body 17 and the front part 16 of the case will be shot forwardly in the direction of flight by the charge, while the tail 25 will be shot in the opposite direction by the gas pressure on the push plate 20. Thus, the push plate 20 is forced backwardly in the tube 18 until the flange of the tube hits the edge of the push plate and pulls the plate and the parachute out of thetail. The tube 18 accordingly has the same function as the bolt 11 in FIG. 1. This version is not suitable as a smoke shell. If a flare is to be used it has to be ignited in its upper e d because the luminous mass here is forced directly into the front part 4 of the case and it cannot stream out rearwardly.

The invention can be varied in a number of ways. The active body, for example, can be connected to the push plate by a number of wires or chains that allow a free movement for some distance until they are fully stretched. The essential thing is that the plate shall remain in its position in the tail for a sufficient period to permit the tail and the active body to have time to gain enough kinetic energy before the wires or chains are fully stretched. The spacing member 8 in FIG. 1 can be omitted if the bolt 11 is made thicker at the end that is attached to the bottom of the active body and/ or is provided with a flange so that the hole in the push plate presses against the latter. A further shoulder similar to the shoulder 10 can be provided in the tail so that the active body is supported in the same way as the push plate 9. The shell according to FIG. 2 can be used with a smoke charge or a luminous charge that is struck in its lower end by the charge 21 if special outstream holes are provided in the wall of either the tube 18 or in the active body itself. The invention can be applied on fin-steering as well as on spinstabilized shells.

What is claimed is:

1. A parachute shell having a divisible case consisting of a head and a tail part and provided with an easily breakable connection between said parts, the head part containing a receptacle for an active body characterized in that the rear end of said receptacle has a backwardly projecting bolt passing through a central hole in a push plate for guiding said plate for a limited axial distance to a stop comprising the head of said bolt by way of a fuze, an ignition channel and a powder charge being located between said receptacle and the push plate, said push plate resting on a support in the tail part of the case, said tail part of the casecarrying a parachute which is attached to the push plate.

2. A parachute shell according to claim 1, characterized in that the leading surface of the push plate is in contact with a spacing ring, the outer diameter of Which is of the same order of magnitude as the outer diameter of the receptacle, said ring forming a supporting flange for the push plate around said powder charge.

3. A parachute shell having a divisible case consisting of a head part and a tail part and provided with an easily breakable connection between said parts, the head part containing a receptacle for an active body, characterized in that the rear end of said receptacle continues into a backwardly projecting tube surrounding a push plate with sleeve for guiding said plate for a limited axial distance to a stop comprising an inwardly directed flange on the end of said tube by way of a fuze, an ignition channel and a powder charge being located between said receptacle and said push plate, said push plate resting on a support in the tail part of the case, said tail part of the case carrying a parachute which is attached to a hold on the push plate.

References Cited UNITED STATES PATENTS 1,312,499 8/1919 Holt l0235.6 1,319,636 10/1919 Wiley 10235.6

FOREIGN PATENTS 859,382 12/1940 France.

BENJAMIN A. BORCHELT, Primary Examiner J. FOX, Assistant Examiner 

